Heretofore, reinforced rubber articles such as tires having a cut or opening therein have been repaired with a patch. Generally the opening is first filled with an uncured gum rubber which is thereafter cured by such means as portable heating units or spotters. If required, a patch is applied to the inner surface of the tire or other article. Usually such a patch is needed if the reinforcing materials in the article, primarily cords or belts have been partially or completely severed, providing a weakened area prone to subsequent failure. In providing a patch reinforced to the same degree as the amount of lost reinforcement, the repaired article is, at least in theory, as strong as before the injury.
Prior art patches fall into two classes, the chemical cure patches which are high in cost and provide only poor adhesion to the substrate and uncured patches which require the use of heat for proper cure and adhesion. Unlike the method of heat application for the gum rubber filler, a rather sophisticated process must be used to cure this latter type of patch, to wit, a tire mold or similar device. Thus when a patch is required, on the spot or in situ repair is exceedingly cumbersome at best and in most cases impossible, requiring the article to be returned to the shop.
The present invention utilizes a cured rubber patch secured to the elastomer substrate through an adhesive system which is curable at ambient temperatures. There is therefore no need for the use of a tire mold to effect repair and the article can easily and quickly be treated in the field, saving both time and expense. The adhesive system utilizes an amine curable polyurethane or other prepolymer and a treating agent.
Considering the prior art, U.S. Pat. Nos. 3,755,261 to VanGulick; 3,888,831 to Kogan; 3,834,934 to Broisman; 3,644,256 also to Broisman; and 3,718,587 to Bhakuni relate to amine curable curing agents, amine curable polymers, or R.F.L. type adhesives. However, these patents lack any suggestion of applicants' treating agent or repair of an elastomer article.
U.S. Pat. No. 3,779,794 to DeSantis relates to a moisture-curable polyurethane sealant primer system, whereas U.S. Pat. No. 4,085,283 to DenOtter relates to flame retardants utilized in cyanuric acid derivatives. Hughson Chemical Division, Lord Corporation, Product No. PS-2682-71 relates to a surface primer for elastomeric substances utilizing a proprietary compound thought to be mono- or dichloroisocyanuric acid. An article entitled "Room Temperature Vulcanizing Adhesive Based on Ethylene-Propylene-Diene Terpolymer," Cantor, Uniroyal, Paper No. 18, presented to the Division of Rubber Chemistry of the American Chemical Society, Denver, Colo., Oct. 10, 1973 relates to various oxidants which effect ambient temperature cures of E.P.D.M.
U.S. Pat. No. 4,136,219 to Oldam relates to a polyurethane paint which is applied to vulcanized rubbers. British Pat. No. 1,352,645 relates to a polyurethane paint which is app1ied to vulcanized rubbers.
U.S. Pat. No. 4,125,522 to Becker relates to a polyurethane adhesive, whereas U.S. Pat. No. 3,966,530 to Cutts relates to triazoline diones which are utilized in lieu of chlorinated or halogenated donors for treating elastomeric surfaces to improve adhesion.
U.S. Pat. No. 4,143,454 to Utsonomiya relates to a method of attaching connecting parts of an offshore structure wherein a liquid rubber is applied over a treating solution which may contain a halogen molecule. As such, this reference lacks applicant's treating agent as well as repair of an elastomeric article having a patch thereon.
U.S. Pat. No. 4,158,378 to Pearson relates to a cured rubber tire having a specific polyurethane therein and to a chlorine water treatment. Hence, Pearson also fails to teach or suggest applicant's recited treating agent as well as the patched article.
British Pat. No. 1,352,645 relates to N- halogen sulfonamide treating agents which halogenize surfaces of synthetic and/or natural rubbers.
U.S. Pat. No. 3,991,255 to Blaskjiewicz relates to the adhesion of a polyurethane to an EPDM surface utilizing various adhesives, however, Blaskjiewicz does not use his treating agent to form a treating layer and utilizes elevated temperatures.
U.S. Pat. No. 4,300,970 to Honda does not disclose amine curable resins or an ambient temperature cure.
U.S. Pat. No. 4,240,852 to Gomberg relates only to the use of a cyanoacrylate adhesive.
U.S. Pat. No. 4,352,704 to Williams relates to applying tire tread to a tire. This patent lacks any suggestion of applicant's treating agent or the repair of a tire aperture.
U.S. Pat. No. 4,327,138 to Hausch fails to disclose a cured rubber patch in repairing a rubber article.
One prior art method of repairing a tire article relates to the utilization of a proprietary compound thought to be a mixture of rubber and accelerators which is applied to the aperture and then cured. In general, a very poor adhesion results and heat is required.